// https://www.acwing.com/problem/content/904/
#include <iostream>
#include <algorithm>
using namespace std;

const int N = 1010;

int n, m;
char a[N], b[N];
int f[N][N];

int main()
{
    cin >> n;
    scanf("%s", a + 1);
    cin >> m;
    scanf("%s", b + 1);
    for (int i = 0; i <= m; i++)
        f[0][i] = i;
    for (int i = 0; i <= n; i++)
        f[i][0] = i;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++)
        {
            f[i][j] = min(f[i - 1][j] + 1, f[i][j - 1] + 1);
            if (a[i] == b[j])
                f[i][j] = min(f[i][j], f[i - 1][j - 1]);
            else
                f[i][j] = min(f[i][j], f[i - 1][j - 1] + 1);
        }
    cout << f[n][m];
    return 0;
}